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<p class="header"><a class="header" href="intro.htm">Orbiter</a> &gt; <a class="header" href="mainmenu.htm">Main menu</a> &gt; Time acceleration</p>

<h1>Time acceleration</h1>

<p>Orbiter allows to accelerate time so that flight plans such as interplanetary transfers that may take years can be simulated in a small fraction of the actual flight time.</p>

<p>The <i>Time acceleration</i> dialog can be openend with <kbd class="ctrl">Ctrl</kbd> <kbd class="ctrl">F2</kbd>, or by selecting <i>Speed</i> from the main menu.</p>

<p>You can adjust the time acceleration speed by either clicking one of the acceleration buttons, which provide speed settings from 0.1 (1/10 of real-time) to 1000 (1000x real time), or by moving the slider, which provides the same range but allows finer step sizes.</p>

<p>Or you can enter a numerical acceleration value directly in the text box. Here you can enter any value in the range from 0.1 to 100000.</p>

<p>To adjust the acceleration without opening the dialog box, use the keyboard shortcuts <kbd>R</kbd> and <kbd>T</kbd> to reduce and increase the time acceleration in steps of 0.1 times and 10 times the current setting, respectively.</p>

<p>You can also use the dialog to pause and resume the simulation, by pressing the <i>Pause/Resume</i> button. The keyboard shortcut for pause/resume is <kbd class="ctrl">Ctrl</kbd> <kbd>P</kbd>. Camera control is active in a paused simulation, so you can toggle between cockpit and external views, select a different target, or move the camara around your target.</p>

<p><b>Warning:</b> High time accelerations can lead to numerical instabilities which may cause problems ranging from reduced accuracy to complete loss of control. Avoid high time acceleration in situations where the spacecraft state changes rapidly (e.g. in low orbit or during atmospheric flight). On the other hand, high acceleration is safe where the state changes slowly, for example during interplanetary transfers or in high orbits.</p>

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